Method of and apparatus for fixing nitrogen.



W. SLLANDIS.

METHOD OF AND APPARATUS FOR mum mnoenu.

APPLICATION FILED APR. 3, 1914, 1,1 033,062, Patented July 14, 1914;

ermine 'rarnnfr o lU E.

W'ALIER S. LANDIS, OF NIAGARA FALLS, YDRK, ASSIGNOR '10 AMERICAN CYANAMID COMPANY, OF NASHVILLE, TENNE$SEE, A CORPORATION OF MAINE.

METHOD OF AND APPARATUS FOR FIXING NITROGEN.

Specification of Letters Patent.

Patented July 1-1, 1914..

Application filed April 3, 1914. Serial No. 829,387.

able others skilled in the art to which itappertains to make and use the same.

This invention relates to a method of and apparatus for fixmg nitrogen and has for Y its object to lessen the cost of as well as the time heretofore required to commercially produce calcium cyanamid.

\Vith these and other objects'in view the invention consists in the novel steps constituting my process and'the novel apparatus hereinafter more fully disclosed and particularly pointed out in the claims.

Referring to the accompanying drawings forming a part of this specification, in which the figure is a diagrammatic sectional view of a can for snaking cyanalnid built in accordance with my invention, 1 indicates the outer shell of any suitable construction, 2 the inner vessel of conducting material for holding calcium carbid," 3 the carbid with which the vessel 2 is charged, i a resistor buried directly in the mass of car bid, ,5 the upper end of the resistor which is conveniently enlarged and extended above the vessel 1., 6 and 7 the lead wires, 8 any suitable cover for said. outer vessel 1, 9 an opening for the admission of nitrogen gas and 10 any suitable vent opening.

Prior to my invention the process of making calcium cyanamid comprised the react ing on carbid by heating to a suitable temperature a small portion of the carbid and supplying nitrogen as the reaction proceeded. In carrying out this old process a cen. tral core of-carbid of greater or less dimensions was provided and a small resistor was inserted in this core for the purpose of heating said core to the reacting temperature. The core was also so constructed as to permit a free flow of nitrogen around the carbon resistor. But it is a well known 7 fact that it is practically impossible to get absolutely pure nitrogen, and that. the usual impurities carried by this gas have an -oxi:

dizing effect on the carb n resistor at the temperatures to which it must be raised. A rapid deterioration of said resistors is a direct result of these impurities, and it -is a further known fact, that the cyanamid industry is, as a consequence, forced to replace these resistors sometimes as often as several times a day, thus not only entailing a loss oi resistors but the loss of considerable time, well as experiencing serious inter ruptions of the heating of the carbid. Fur- :ther experieuce'has taught me that when the carbid is heated to a reacting temperature in the presence of nitrogen it stands up as a hard,impervious mass of cyanamid around the core, the thickness of which mass will increase 23 the process continues. This said impervious mass surrounding thecore so greatly hinders the feeding of the nitrogen therethrough to fresh carbid, that in reality it lenders the core useless, for intact, the core *annot furnish a means for iiicilitating the feeding of the nitrogen after the real tion has proceeded for some time, as has been believed heretofore. As a matter of fact, observation has convinced me, that the nitrogen is fed to the carbid mass after the process is well under way, not through the discovered thatan open central core in the can is useless, and that I can avoid the. above objections and improve the process of com mercially producing cyanamid by embedding the carbon or otherresistor directly in the carbid mass as above indicated.

I may use the same form of resistor 4: as heretofore, but by electrically connecting its lower. end to the cam 2, and by permitting its upper end 5 to project outslde the vessel 1 facilitate the electrical connections,

and .urther eliminate the oxidizing efi'ects ofthe impurities carried by the nitrogen, except at the point 11 between the vessels 1 and 2. The resistor, however, at this point isat a lower temperature and'has a larger'cross section, so the oxidizing effects may be neglected. Actual experience has changing 6t tl efsame during each rim.

,proved that this method of igniting the cartherefore the total heat given off is not as high as it would; otherwise be. AccordinglyI prefer in both the old and new proc ess to introduceheat to the mas from an outside source in order to facilitate the nitrification'. This may be conveniently accomplished by maintaining a high temperature in theresistor throughout the process.

'What I claim is 1. The process of forming nitrogen compounds through the reaction of nitrogen upon carbid, which consists in burying the I resistor used for supplying heat to the chargedirectly in the mass of the said carbid, and out 0F direct contactwith the circulating excess nitrggen in said charge; and raising said resistor to a temperature suflicient to cause the desired reaction, while feeding nitrogen to the charge, substantially as described. 7

2. The process of fixing nitrogen which consists in providing a suitable charge of jgalcium carbid; burying a resistor directly in the mass of said charge and out of direct contact with the circulating excess of nitrogen through the said charge; preventing destruetion through oxidizing efi'ects of said" resistor outside of said charge; and raising said resistor to a temperature sufiicient to cause the desired reaction, while feeding nitrogen to the charge, substantially as described.

3. In an apparatus for fixing atmospheric nitrogen, the combination of a suitable container adapted to hold a charge of carbid; a resistor entering said container and adapted to be directly buried in said charge out of direct contact with the circulating excess of nitrogenthrough the interstices of said charge; means for decreasing the rate of destruction of said resistor outside of said charge through oxidizing actions; means for passing a current of electricity through said resistor; and means for feeding nitrogen to said charge, substantially as described.-

4. The process of fixing nitrogen which consists in providing a suitable charge of calcium car-bid; burying a resistor directly in the mass of said charge and out of direct contact with the circulating exces of nitrogen through the said charge; preventing the destruction through oxidizing efiects of said resistor outside of said charge; raising said resistor to a temperature sulficient to cause the desired reaction, while feeding nitrogen to the charge; and continuously supplying heat from an outside source to said mass during the process of nitrification, substan tially as described.

In testimony whereof I afiix my signature, in presence of two witnesses.

WALTER S. LANDIS. Witnesses:

I E. D. MALLAM,

. J. L. DOLAN. 

